U.S. Pat. No. 4,269,723 to Barford, et al., discloses a process for making lavatory cleansing blocks by tableting a free flowing particulate mix consisting essentially of on a weight basis from 5 to 90% of a surface active component and from 0.5 to 75% of one or more binders selected from clays and water soluble or water dispersible gel forming organic polymeric materials. Of the water soluble polymeric binders, Barford makes mention of chemically modified celluloses such as ethyl cellulose, methyl cellulose, sodium carboxymethyl cellulose, ethyl hydroxyethyl cellulose, and the like. Various optional components are also mentioned by Barford; namely, dyestuffs, perfume, water soluble fillers, water softening or chelating agents, solid water soluble acids, inert water insoluble inorganic or organic fillers, tablet lubricants, and agents having disinfecting or germicidal activity.
U.S. Pat. No. 4,460,490 to Barford, et al., discloses a freestanding lavatory cleansing block that comprises a shaped body formed of a slow dissolving cleaning composition containing a surface active agent and a tablet comprising a bleaching agent embedded in or adhered to the shaped body. The shaped body, according to the '490 patent, may be melt cast, tableted, or extruded, depending upon the geometry of the shaped body. The shaped body preferably comprises the aforesaid surface active agent and a solubility control agent, for example, a water soluble or water dispersible gel forming polymer, for example, chemically modified celluloses.
U.S. Pat. No. 4,438,015 to Huber discloses lavatory cleansing blocks comprising as a solid carrier base a mixture comprising a major proportion of a nonionic surface active compound and a minor proportion of a partially esterified copolymer of vinylmethyl ether and maleic anhydride (PVM/MA). The blocks of Huber are melt cast.
U.S. Pat. No. 4,043,931 to Jeffrey, et al., discloses a lavatory cleansing block comprising a solid carrier base which is a mixture of two or more nonionic surface active agents, one of which is relatively insoluble in water and the other of which is relatively soluble in water. Suitable relatively water insoluble nonionic surface active agents are the mono- and dialkanolamides of long chain fatty acids, and polyalkoxylated fatty alcohols containing up to 6 moles of alkoxide. Suitable relatively water soluble surface active agents include polyalkoxylated fatty alcohols of more than 6 alkyleneoxy units per molecule and the alkyleneoxy block copolymers. The lavatory block of Jeffrey may optionally include perfume, dyestuff, germicide, and fillers, the latter being for example, a water softener such as a alkali metal polyphosphate. The blocks of Jeffrey are made by tableting.
U.S. Pat. No.4,229,410 to Kosti discloses a bacteriostatic toilet element comprising a water sensitive, water soluble or swellable binding agent and a bacteriostatic and/or deodorizing and/or coloring agent. Kosti's element may be melt cast or extruded.
U.S. Pat. No. 4,119,578 to Daeninckx, et al., discloses a hydrosoluble bar obtained by extrusion, the bar containing paraffin sulfonate as an extrusion aid.